3959 lines
93 KiB
Plaintext
3959 lines
93 KiB
Plaintext
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{
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"nbformat": 4,
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"nbformat_minor": 0,
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"metadata": {
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"kernelspec": {
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"display_name": "Python 3",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.8.5"
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},
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"colab": {
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"provenance": [],
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"collapsed_sections": [
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"wugqn01Eo6uK"
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]
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}
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},
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {
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"id": "kon_YiKko6tH"
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},
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"source": [
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"# CS221 Python Review Tutorial\n",
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"\n",
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"Presenter: Dilara\n",
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"\n",
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"Hi! In this tutorial, we will review the basics of Python. This tutorial is largely based on the [CS224N Python Tutorial](http://web.stanford.edu/class/cs224n/readings/cs224n-python-review-code-updated.zip), prepared by Angelica Sun, as well as the [W3Schools Python Tutorial](https://www.w3schools.com/python/).\n",
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"\n",
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"## Contents\n",
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"\n",
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"* Fundamentals\n",
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"* Control Flows\n",
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"* Functions\n",
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"* Classes\n",
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"* Iterables\n",
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"* Q&A"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {
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"id": "g5MyzBMeo6tW"
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},
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"source": [
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"## Fundamentals\n",
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"\n",
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"### Syntax\n",
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"\n",
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"We can run a Python file through the command line as follows:\n",
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"\n",
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"```\n",
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"python example.py\n",
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"```\n",
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"\n",
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"This line of code will call the `Python` version that is bound to `python` alias in the command line environment. You would sometimes get `Module Not Found` errors. One of the first troubleshooting steps you can do is to actually check whether you are using the correct `Python` binary. To learn which `Python` is being called, you can run:\n",
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"\n",
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"```\n",
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"which python\n",
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"```\n",
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"\n",
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"Let's start with printing \"Hello World!\""
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]
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},
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{
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"cell_type": "code",
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"metadata": {
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"colab": {
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"base_uri": "https://localhost:8080/"
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},
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"id": "bS-2lFSmRicu",
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"outputId": "ba75ed43-ae72-4982-ad58-ca454cba5697"
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},
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"source": [
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"# Printing Hello World!\n",
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"print(\"Hello World!\")"
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],
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"execution_count": null,
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"outputs": [
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{
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"output_type": "stream",
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"text": [
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"Hello World!\n"
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],
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"name": "stdout"
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}
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {
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"id": "SKPRPmIJTWD0"
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},
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"source": [
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"Indentation is important in `Python`. Lines of code that are in the same block of code should be indented with the same number of spaces."
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]
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},
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{
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"cell_type": "code",
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"metadata": {
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"colab": {
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"base_uri": "https://localhost:8080/",
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"height": 132
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},
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"id": "Ly6ZxRUCTVbd",
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"outputId": "734a3e78-10ee-435e-bbbc-b0084dd08901"
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},
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"source": [
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"# Example of an Indentation Error\n",
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|
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"print(\"Hello\")\n",
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" print(\"Hello World!\")"
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],
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"execution_count": null,
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"outputs": [
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{
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"output_type": "error",
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"ename": "IndentationError",
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"evalue": "ignored",
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"traceback": [
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"\u001b[0;36m File \u001b[0;32m\"<ipython-input-4-de16869d016e>\"\u001b[0;36m, line \u001b[0;32m3\u001b[0m\n\u001b[0;31m print(\"Hello World!\")\u001b[0m\n\u001b[0m ^\u001b[0m\n\u001b[0;31mIndentationError\u001b[0m\u001b[0;31m:\u001b[0m unexpected indent\n"
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]
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}
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {
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"id": "9FsiH-Z4Ul3c"
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||
|
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},
|
||
|
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"source": [
|
||
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"You can use line comments or block comments to comment code in `Python`."
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]
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},
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{
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"cell_type": "code",
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"metadata": {
|
||
|
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"colab": {
|
||
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"base_uri": "https://localhost:8080/"
|
||
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},
|
||
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"id": "xbl9Q9ECUlTW",
|
||
|
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"outputId": "7903b8e5-08a7-437b-e408-5e0d8d7f63e8"
|
||
|
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},
|
||
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"source": [
|
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|
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"# Line comment\n",
|
||
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"\n",
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"\"\"\"\n",
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"Block comment\n",
|
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"\"\"\"\n",
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"\n",
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"print(\"Hi!\")"
|
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],
|
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"execution_count": null,
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||
|
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"outputs": [
|
||
|
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{
|
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"output_type": "stream",
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|
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"text": [
|
||
|
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"Hi!\n"
|
||
|
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],
|
||
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"name": "stdout"
|
||
|
|
}
|
||
|
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]
|
||
|
|
},
|
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|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "0ObB8VtCUEsP"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"### Variables\n",
|
||
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"\n",
|
||
|
|
"In `Python`, variables are defined by assigning value to them. There is no need to explicitly declare the type of a variable."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "wZFgDcM4o6te",
|
||
|
|
"outputId": "802cacd1-078a-44e1-ad6d-560adb168a78"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# str, immutable\n",
|
||
|
|
"var = \"hello\" # ''\n",
|
||
|
|
"print(type(var))"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"<class 'str'>\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "PqdLmxccXCGa",
|
||
|
|
"outputId": "ab83ac06-17dd-4ec6-ac11-822fe13fafe6"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# int, immutable\n",
|
||
|
|
"var = 10\n",
|
||
|
|
"print(type(var))"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"<class 'int'>\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "ZmvDAvPbWzBg",
|
||
|
|
"outputId": "0e27eafa-ef5c-4c9d-a4fe-a03e20dd0a4a"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# float, immutable\n",
|
||
|
|
"var = 10.0\n",
|
||
|
|
"print(type(var))"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"<class 'float'>\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "ADVFU3l-XGW8",
|
||
|
|
"outputId": "1d1af822-e407-4ae3-8bf9-ed289645c98d"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# bool, immutable\n",
|
||
|
|
"var = True # False\n",
|
||
|
|
"print(type(var))"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"<class 'bool'>\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "H3iFhJRlylvB",
|
||
|
|
"outputId": "847101a5-35f6-4b8d-8cf3-8f6a42e73ca1"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# tuple, immutable\n",
|
||
|
|
"# collections of objects\n",
|
||
|
|
"var = (8,9)\n",
|
||
|
|
"print(type(var))"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"<class 'tuple'>\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "kQldl4vcXJl9",
|
||
|
|
"outputId": "0e4f4179-8861-4552-f700-9554064bb118"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# list\n",
|
||
|
|
"var = [1,2,3]\n",
|
||
|
|
"print(type(var))"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"<class 'list'>\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "e7rA5rhlW2Ua",
|
||
|
|
"outputId": "7312dbe9-37b6-4284-89bd-874efea1bc7b"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# None\n",
|
||
|
|
"var = None\n",
|
||
|
|
"print(type(var))"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"<class 'NoneType'>\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "b5bFUVlGV2IH"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can re-assign a variable to a different type."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "zYyhlcEJV6RK",
|
||
|
|
"outputId": "44ace863-6982-4335-84e3-61981787fe75"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"var = 10\n",
|
||
|
|
"print(type(var))\n",
|
||
|
|
"var = \"Hi 221!\"\n",
|
||
|
|
"print(type(var))"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"<class 'int'>\n",
|
||
|
|
"<class 'str'>\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "pXsTTdxhXczT"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can cast variables to different types."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "sDtG68Vqo6tf",
|
||
|
|
"outputId": "d6a54576-fdcd-4b84-8c35-628c8c9155dc"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"a = 10\n",
|
||
|
|
"print(a, type(a))\n",
|
||
|
|
"\n",
|
||
|
|
"b = str(a)\n",
|
||
|
|
"print(b, type(b))\n",
|
||
|
|
"\n",
|
||
|
|
"c = int(b)\n",
|
||
|
|
"print(c, type(c))\n",
|
||
|
|
"\n",
|
||
|
|
"d = float(c)\n",
|
||
|
|
"print(d, type(d))"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"10 <class 'int'>\n",
|
||
|
|
"10 <class 'str'>\n",
|
||
|
|
"10 <class 'int'>\n",
|
||
|
|
"10.0 <class 'float'>\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "d88q8KFiYkU5"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Variable names are sensitive to case."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "Z35h7buwYnkK",
|
||
|
|
"outputId": "5eadd3bd-fb31-40ec-ca57-7bbcca27501f"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"a = 10\n",
|
||
|
|
"A = \"221\"\n",
|
||
|
|
"print(a == A)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"False\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "EQ9WzOLpY7D5"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can assign values to multiple variables in one line."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "CgTUIBXKY-K8",
|
||
|
|
"outputId": "3201e9c7-d630-481a-e7ed-4a1de5774847"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"a, b, c = \"I\", \"love\", \"CS221\"\n",
|
||
|
|
"print(a)\n",
|
||
|
|
"print(b)\n",
|
||
|
|
"print(c)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"I\n",
|
||
|
|
"love\n",
|
||
|
|
"CS221\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "AJjUP9Laac2E"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can also print multiple variables in one `print` statement by seperating them with a comma."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "_GZ7VQXEaelm",
|
||
|
|
"outputId": "2fd59fc9-0bf7-4429-820d-34c9d7008bb1"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"a, b, c = \"I\", \"love\", \"CS221\"\n",
|
||
|
|
"print(a, b, c)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"I love CS221\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "GeHeASLcZpcu"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"### Operations\n",
|
||
|
|
"\n",
|
||
|
|
"#### Number Operations\n",
|
||
|
|
"\n",
|
||
|
|
"You can use math operators on variables and literals."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "V5sP_1QQba1U",
|
||
|
|
"outputId": "f68059e7-0bde-43e9-e59b-7d120f7def6d"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"var = 10\n",
|
||
|
|
"print(var + 4)\n",
|
||
|
|
"print(var - 4)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"14\n",
|
||
|
|
"6\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "Wef3S0VdbofN",
|
||
|
|
"outputId": "b603e23d-a790-4b58-f8ea-ca9374ea7d6d"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# Multiply with *\n",
|
||
|
|
"print(var * 4)\n",
|
||
|
|
"\n",
|
||
|
|
"# Raise power with **\n",
|
||
|
|
"print(var ** 4)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"40\n",
|
||
|
|
"10000\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "nr4ZbHlZbgTJ",
|
||
|
|
"outputId": "7603c928-5570-4a3f-f637-e80a874148b9"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# Float division with /\n",
|
||
|
|
"print(var / 4)\n",
|
||
|
|
"\n",
|
||
|
|
"# Integer division with //\n",
|
||
|
|
"print(var // 4)\n",
|
||
|
|
"\n",
|
||
|
|
"# Integer division is the same as dividing then casting\n",
|
||
|
|
"print(int(var / 4))"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"2.5\n",
|
||
|
|
"2\n",
|
||
|
|
"2\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "wjSXnKMtcS1I"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can also use compounding operators for each."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "l304SQEdcSIn",
|
||
|
|
"outputId": "17c253fa-486a-4ca5-a693-84aa588ee8cd"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"print(var)\n",
|
||
|
|
"var **= 4\n",
|
||
|
|
"print(var)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"10\n",
|
||
|
|
"10000\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/",
|
||
|
|
"height": 167
|
||
|
|
},
|
||
|
|
"id": "4_d5vlWNiBke",
|
||
|
|
"outputId": "284aa733-ea39-4d36-b5d6-dd4dbe27345b"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"--a"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "error",
|
||
|
|
"ename": "TypeError",
|
||
|
|
"evalue": "ignored",
|
||
|
|
"traceback": [
|
||
|
|
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
|
||
|
|
"\u001b[0;31mTypeError\u001b[0m Traceback (most recent call last)",
|
||
|
|
"\u001b[0;32m<ipython-input-22-8076006b0952>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0ma\u001b[0m \u001b[0;34m+=\u001b[0m \u001b[0;36m1\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
|
||
|
|
"\u001b[0;31mTypeError\u001b[0m: can only concatenate str (not \"int\") to str"
|
||
|
|
]
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "NTSog3DUco7f"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"#### Boolean Operations\n",
|
||
|
|
"\n",
|
||
|
|
"Boolean operations are `not`, `and`, and `or`."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "aP6-LpBIo6tj",
|
||
|
|
"outputId": "9cee0dd9-a185-4339-989b-331ebb46909a"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"print(not True)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"False\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "6vYrzWqkc70o",
|
||
|
|
"outputId": "792ba493-b264-4fba-f5af-7508920a21a1"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"print(True and False)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"False\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "cKIDh4cYdCct",
|
||
|
|
"outputId": "45a78590-cbfe-4f22-eea3-24c287911476"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"var = True or False\n",
|
||
|
|
"print(var)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"True\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "DjDQFW7bdclb"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"`==` checks value equality. `!=` checks inequality."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "iHCGui23difG",
|
||
|
|
"outputId": "4e075454-60f0-4740-efe4-2d4faca6c171"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"a = \"221\"\n",
|
||
|
|
"b = \"221\"\n",
|
||
|
|
"print(a == b)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"True\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "9z0wa6SweCIO"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Operations `>=` and `<=` are available when the order is defined. Refer to this [link](https://www.geeksforgeeks.org/sorting-objects-of-user-defined-class-in-python/) to learn how to define order for user defined classes."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "2LJGhoBQeHd0",
|
||
|
|
"outputId": "a7a612c3-003c-4cd3-ff12-dc40a20d0878"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"a = 6\n",
|
||
|
|
"b = 8\n",
|
||
|
|
"print(b >= a)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"True\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "SZ6GfhgOdQz5"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"#### String Operations\n",
|
||
|
|
"\n",
|
||
|
|
"For strings, double quotes and single quotes are equivalent."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "i-EFzJA7XhKg",
|
||
|
|
"outputId": "7050fbaf-5f19-44cb-e049-b46bdb5c5fab"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"a = \"221\"\n",
|
||
|
|
"b = '221'\n",
|
||
|
|
"print(a >= b)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"True\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "WL3TFqR5e-ux"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can get the length of a string. `len` function can be used on any `iterable`. Strings are iterables in `Python`, so they can just be treated as arrays."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "1W1ORPaLfDul",
|
||
|
|
"outputId": "b0f41e82-8750-4b72-b7ba-a53a61af281b"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"a = \"I love CS221!\"\n",
|
||
|
|
"print(len(a))"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"13\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "aL2NGVmHfLPs"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can access specific elements of a string through their indices."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "1f7zboZGfYOJ",
|
||
|
|
"outputId": "3467d97e-5514-48a9-e120-c6c15b59098f"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"print(a[0])"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"I\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "ZguxFX8HffQT",
|
||
|
|
"outputId": "228df4b1-de4e-4aa2-ee31-86de5cd498f9"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# [start_index, end_index)\n",
|
||
|
|
"print(a[2:6])"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"love\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "pr1qCjllhORU"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can lower all the charaters in a string."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "Kulr99AshNfA",
|
||
|
|
"outputId": "6e8703b9-8a4c-460e-fc5c-abb41adf0d60"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"print(a.lower())"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"i love cs221!\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "VYznaNf0hZtX"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can multiply a string."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "SGaBRMZlhdYr",
|
||
|
|
"outputId": "38405ae2-1eb4-42bc-e1af-80b96f5c1b7c"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"print(a * 4)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"I love CS221!I love CS221!I love CS221!I love CS221!\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "SsyUJxalhgKj"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can concatenate strings."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "-kNbX0ZOhsGz",
|
||
|
|
"outputId": "2838a2c7-7e84-404f-a1cc-6777dde5d1d7"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"b = \"How about you?\"\n",
|
||
|
|
"c = a + \" \" + b\n",
|
||
|
|
"print(c)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"I love CS221! How about you?\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "1eWp-_bdh4xg"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can check if a substring exists in a string. We can also get the start index of the first occurence of a substring."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "z-KZ6PsVh5cc",
|
||
|
|
"outputId": "713b0b71-c603-46a2-97c3-b9e395bc8dfd"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"print(\"love\" in a)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"True\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"id": "UYaExPmsi3M2"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"if \"love\" not in a:\n",
|
||
|
|
" print(\"yeyyy\")"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": []
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "b8Y9YInEkj8U",
|
||
|
|
"outputId": "ea09a33a-c5f5-4177-808d-ed384315e82a"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"print(\"love\" not in a)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"False\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "bfB_vufGiHNE",
|
||
|
|
"outputId": "113b4cc4-5300-4b6a-9a9b-45c61fd5de05"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"a.index(\"love\")"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"text/plain": [
|
||
|
|
"2"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 34
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "lGD4FEI7iMM7"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can split a string."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "IlmNdwM1iN04",
|
||
|
|
"outputId": "c8e2cc05-d4e7-41d0-eddd-f55bf2bf7c2b"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# The default delimiter is a space, but we can pass a different delimiter\n",
|
||
|
|
"a.split()\n"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"text/plain": [
|
||
|
|
"['I', 'love', 'CS221!']"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 35
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "l80WOUvBjt0G",
|
||
|
|
"outputId": "7bb6ab9d-60ac-4057-d288-7ff218568541"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"a.split('2')"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"text/plain": [
|
||
|
|
"['I love CS', '', '1!']"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 36
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "-r8JrMpLiz2g"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can combine a list."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "Vs7mynmvi5Mk",
|
||
|
|
"outputId": "e2dc4469-f0c4-4bb2-c8c3-58a0efd6b0fa"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"a_splitted = a.split()\n",
|
||
|
|
"print(a_splitted)\n",
|
||
|
|
"\n",
|
||
|
|
"a_joined = '-'.join(a_splitted)\n",
|
||
|
|
"print(a_joined)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"['I', 'love', 'CS221!']\n",
|
||
|
|
"I-love-CS221!\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "_eZIL5U6jJUj"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can format variables in strings."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "ftkUo2kho6tk",
|
||
|
|
"outputId": "d03decbb-8110-4d19-ba38-d80432d26238"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"pi = 3.14159\n",
|
||
|
|
"print(\"Pi is %.2f!\"%(pi))\n"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"Pi is 3.14!\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/",
|
||
|
|
"height": 35
|
||
|
|
},
|
||
|
|
"id": "VVZolJWRkJjR",
|
||
|
|
"outputId": "c90054be-475f-42ad-da18-48105c9df6c2"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"f\"Pi is {pi}!\""
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"application/vnd.google.colaboratory.intrinsic+json": {
|
||
|
|
"type": "string"
|
||
|
|
},
|
||
|
|
"text/plain": [
|
||
|
|
"'Pi is 3.14159!'"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 42
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "RMivqfyxkBVj"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"## Control Flows\n",
|
||
|
|
"\n",
|
||
|
|
"### For Loops\n",
|
||
|
|
"\n",
|
||
|
|
"We can use loops to iterate over iterables, such as strings or arrays."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "cHziqbEQkWab",
|
||
|
|
"outputId": "b2d43fd1-c8ba-49ea-b70b-7a869159c6e9"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"s = \"I love 221!\"\n",
|
||
|
|
"for character in s:\n",
|
||
|
|
" print(character)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"I\n",
|
||
|
|
" \n",
|
||
|
|
"l\n",
|
||
|
|
"o\n",
|
||
|
|
"v\n",
|
||
|
|
"e\n",
|
||
|
|
" \n",
|
||
|
|
"2\n",
|
||
|
|
"2\n",
|
||
|
|
"1\n",
|
||
|
|
"!\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "bbuQrxDQkuaK",
|
||
|
|
"outputId": "c958107a-6351-4c3e-d504-9b2cf1b1e4e0"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"arr = ['a','b','c','d','e','f']\n",
|
||
|
|
"index = 0\n",
|
||
|
|
"for char in arr:\n",
|
||
|
|
" print(char)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"a\n",
|
||
|
|
"b\n",
|
||
|
|
"c\n",
|
||
|
|
"d\n",
|
||
|
|
"e\n",
|
||
|
|
"f\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "1BmvK_0Nlmhr"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"If we also want to keep track of the iteration number, we can use the `enumerate` function."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "77WtGYRDlr4x",
|
||
|
|
"outputId": "95d459e9-5247-4a39-bfac-df117527a840"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"for i, char in enumerate(a):\n",
|
||
|
|
" print(i, char)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"0 I\n",
|
||
|
|
"1 \n",
|
||
|
|
"2 l\n",
|
||
|
|
"3 o\n",
|
||
|
|
"4 v\n",
|
||
|
|
"5 e\n",
|
||
|
|
"6 \n",
|
||
|
|
"7 C\n",
|
||
|
|
"8 S\n",
|
||
|
|
"9 2\n",
|
||
|
|
"10 2\n",
|
||
|
|
"11 1\n",
|
||
|
|
"12 !\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "l8C5T16Pk2sJ"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can iterate a set number of times using the `range` function."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "_m_pGCQfkdyZ",
|
||
|
|
"outputId": "4c4a5861-2d09-40b4-a998-b3b318adf1b9"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# Same as for (int i = 0; i < 4; i++)\n",
|
||
|
|
"for i in range(4):\n",
|
||
|
|
" print(i)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"0\n",
|
||
|
|
"1\n",
|
||
|
|
"2\n",
|
||
|
|
"3\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "b4GtKTHnmKoF"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can use different ranges as well. `range` function can take 3 parameters:\n",
|
||
|
|
"\n",
|
||
|
|
"`range(start-inclusive, stop-exclusive, step)`"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"id": "hm4pCCORmOR4",
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"outputId": "749a7f96-144f-42bd-bfbe-c195caf3ce9c"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# Same as for (int = 2; i > -3, i =- 2)\n",
|
||
|
|
"for i in range(2, -3, -2):\n",
|
||
|
|
" print(i)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"2\n",
|
||
|
|
"0\n",
|
||
|
|
"-2\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "N9w2GNvtm7VA"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"### While Loops\n",
|
||
|
|
"\n",
|
||
|
|
"We can also use `while` loops.\n"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "LnHP2aTYo6tm",
|
||
|
|
"outputId": "7ee3f625-37e7-4b8c-c172-9e71cb5e60c0"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"ind = 0\n",
|
||
|
|
"while ind < 5:\n",
|
||
|
|
" print(ind)\n",
|
||
|
|
" ind +=1\n",
|
||
|
|
" break"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"0\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "z05_SKqQnPms"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"### If Condition\n",
|
||
|
|
"\n",
|
||
|
|
"We can execute a portion of code based on conditions."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "WCqQE7_To6tk",
|
||
|
|
"outputId": "e3bc2173-c53f-4cc6-bb82-155fed8723bc"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"operation = \"add\"\n",
|
||
|
|
"num = 6\n",
|
||
|
|
"if operation == \"add\":\n",
|
||
|
|
" print(\"Adding: \", num + num)\n",
|
||
|
|
"elif operation == \"multiply\":\n",
|
||
|
|
" print(\"Multiplying: \", num * num)\n",
|
||
|
|
"\n",
|
||
|
|
"elif\n",
|
||
|
|
"\n",
|
||
|
|
"elif ...\n",
|
||
|
|
"else:\n",
|
||
|
|
" print(\"Operation is not defined.\")"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"Adding: 12\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "xeDkzJBXoTZD"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can check for `None` objects with `if`."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "blav1CAeoZfS",
|
||
|
|
"outputId": "96ebb6a8-d717-439b-c67b-8fcf09b7706a"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"a = None\n",
|
||
|
|
"if a:\n",
|
||
|
|
" print(\"not None\")\n",
|
||
|
|
"else:\n",
|
||
|
|
" print(\"None\")"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"None\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "1e29DwZ1leiE",
|
||
|
|
"outputId": "1ad59c56-e3ca-466f-83e7-d0f6ad47e967"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"if a is None:\n",
|
||
|
|
" print('yes')"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"yes\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "iWdhY8sRorom"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can check for empty arrays or strings of length 0 with `if`."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"id": "MQxr8Gy-oqwT"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"arr = ''\n",
|
||
|
|
"if arr:\n",
|
||
|
|
" print(\"not empty\")"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": []
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "XqWq5ddao4oX",
|
||
|
|
"outputId": "87cbc6c2-52ad-4b48-d850-b834e5dfa264"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"s = ''\n",
|
||
|
|
"if s:\n",
|
||
|
|
" print(\"not empty\")\n",
|
||
|
|
"else:\n",
|
||
|
|
" print(\"empty\")"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"empty\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "TukPtGOppEhE"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"## Functions\n",
|
||
|
|
"\n",
|
||
|
|
"We can define functions as shown in the following code block. Make sure to define your functions before calling them!"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"id": "l4LLGV4po6to"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# Define the function\n",
|
||
|
|
"def example_func(a, b):\n",
|
||
|
|
" pass\n",
|
||
|
|
"\n",
|
||
|
|
"# Call the function\n",
|
||
|
|
"example_func(5, 10)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": []
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "8M_JaXHupamx"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Functions may have optional parameters."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "0IdV7JXdo6to",
|
||
|
|
"outputId": "3d6f610f-8172-4705-9f48-ef1d2fd1a569"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# Function checking whether the variable is withing a range\n",
|
||
|
|
"def check_range(a, min_val = 0, max_val=10):\n",
|
||
|
|
" return min_val < a < max_val\n",
|
||
|
|
"\n",
|
||
|
|
"# Calling the function\n",
|
||
|
|
"check_range(5, max_val=3)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"text/plain": [
|
||
|
|
"False"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 60
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "K3_NJKzJF813"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Params of immutable types are passed by value. Mutable types are passed by reference."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "RFNeNP_cGGSt",
|
||
|
|
"outputId": "5bb98afa-7b54-4f06-ff14-9cc96b79d5d3"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"def example_function(variable):\n",
|
||
|
|
" variable = 10\n",
|
||
|
|
" print(variable)\n",
|
||
|
|
"\n",
|
||
|
|
"a = 15\n",
|
||
|
|
"print(a)\n",
|
||
|
|
"example_function(a)\n",
|
||
|
|
"print(a)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"15\n",
|
||
|
|
"10\n",
|
||
|
|
"15\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "duEddPKxGUBC",
|
||
|
|
"outputId": "9ad4f58c-60eb-4203-d772-00b4b586b24a"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"def example_function(variable):\n",
|
||
|
|
" variable[0] = 10\n",
|
||
|
|
" print(variable)\n",
|
||
|
|
"\n",
|
||
|
|
"a = [0,1,2,3,4]\n",
|
||
|
|
"print(a)\n",
|
||
|
|
"example_function(a)\n",
|
||
|
|
"print(a)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"[0, 1, 2, 3, 4]\n",
|
||
|
|
"[10, 1, 2, 3, 4]\n",
|
||
|
|
"[10, 1, 2, 3, 4]\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "1V2GEx-4G8-j"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"If you want to prevent your function from the original variables, you can make a deep copy inside your function before using your parameters."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "H8qXvx1zHJIV",
|
||
|
|
"outputId": "5014ab82-4590-48ba-8d19-c18a67928b18"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"import copy\n",
|
||
|
|
"\n",
|
||
|
|
"def example_function(variable):\n",
|
||
|
|
" # Alternative 1\n",
|
||
|
|
" variable = variable[:]\n",
|
||
|
|
"\n",
|
||
|
|
" # Alternative 2\n",
|
||
|
|
" variable = copy.deepcopy(variable)\n",
|
||
|
|
"\n",
|
||
|
|
" variable[0] = 10\n",
|
||
|
|
" print(variable)\n",
|
||
|
|
"\n",
|
||
|
|
"a = [0,1,2,3,4]\n",
|
||
|
|
"print(a)\n",
|
||
|
|
"example_function(a)\n",
|
||
|
|
"print(a)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"[0, 1, 2, 3, 4]\n",
|
||
|
|
"[10, 1, 2, 3, 4]\n",
|
||
|
|
"[0, 1, 2, 3, 4]\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "Au7--qehqJs-"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Functions can access variables in their parent block's scope."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "A_ZbpCQYqQFO",
|
||
|
|
"outputId": "f7c02e87-59d9-4e8c-8185-1048869c0582"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"outside_variable = \"This is an outside variable!\"\n",
|
||
|
|
"\n",
|
||
|
|
"def some_function():\n",
|
||
|
|
" print(outside_variable)\n",
|
||
|
|
"\n",
|
||
|
|
"print(outside_variable)\n",
|
||
|
|
"some_function()"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"This is an outside variable!\n",
|
||
|
|
"This is an outside variable!\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "Cbl0hCogskjY"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Functions can't change the values of the outside variables the same way."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/",
|
||
|
|
"height": 340
|
||
|
|
},
|
||
|
|
"id": "U7gZBMKgskCB",
|
||
|
|
"outputId": "216999cf-c717-4c00-a3b6-96fce6a11d93"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"outside_variable = \"This is an outside variable!\"\n",
|
||
|
|
"\n",
|
||
|
|
"def some_function():\n",
|
||
|
|
" print(outside_variable)\n",
|
||
|
|
" outside_variable = \"Function changed the outside variable\"\n",
|
||
|
|
"\n",
|
||
|
|
"print(outside_variable)\n",
|
||
|
|
"some_function()"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"This is an outside variable!\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"output_type": "error",
|
||
|
|
"ename": "UnboundLocalError",
|
||
|
|
"evalue": "ignored",
|
||
|
|
"traceback": [
|
||
|
|
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
|
||
|
|
"\u001b[0;31mUnboundLocalError\u001b[0m Traceback (most recent call last)",
|
||
|
|
"\u001b[0;32m<ipython-input-64-304d37abea01>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m 6\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 7\u001b[0m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0moutside_variable\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 8\u001b[0;31m \u001b[0msome_function\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
|
||
|
|
"\u001b[0;32m<ipython-input-64-304d37abea01>\u001b[0m in \u001b[0;36msome_function\u001b[0;34m()\u001b[0m\n\u001b[1;32m 2\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 3\u001b[0m \u001b[0;32mdef\u001b[0m \u001b[0msome_function\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 4\u001b[0;31m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0moutside_variable\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m 5\u001b[0m \u001b[0moutside_variable\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0;34m\"Function changed the outside variable\"\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 6\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n",
|
||
|
|
"\u001b[0;31mUnboundLocalError\u001b[0m: local variable 'outside_variable' referenced before assignment"
|
||
|
|
]
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "ehsOEdqrs2jE"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can resolve this error using the `global` key."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "DYGLidivs9nC",
|
||
|
|
"outputId": "d6096b55-3ade-4a53-fe8d-7dca850b3abc"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"outside_variable = \"This is an outside variable!\"\n",
|
||
|
|
"\n",
|
||
|
|
"def some_function():\n",
|
||
|
|
" global outside_variable\n",
|
||
|
|
" outside_variable = \"Function changed the outside variable!\"\n",
|
||
|
|
"\n",
|
||
|
|
"print(outside_variable)\n",
|
||
|
|
"some_function()\n",
|
||
|
|
"print(outside_variable)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"This is an outside variable!\n",
|
||
|
|
"Function changed the outside variable!\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "ibT51hVsrhlj"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"If a variable of the same name is defined in a function, the later definition overwrites the former only in the function scope."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "JuZRURz4rgph",
|
||
|
|
"outputId": "9fc8f387-55c4-410f-f75a-13af6486d1e8"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"variable = \"This is an outside variable!\"\n",
|
||
|
|
"\n",
|
||
|
|
"def some_function(variable=\"Function variable.\"):\n",
|
||
|
|
" print(variable)\n",
|
||
|
|
"\n",
|
||
|
|
"print(variable)\n",
|
||
|
|
"some_function()\n",
|
||
|
|
"print(variable)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"This is an outside variable!\n",
|
||
|
|
"Function variable.\n",
|
||
|
|
"This is an outside variable!\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "AKxBN3tGrZut"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Variables defined in a function can't be accessed outside."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/",
|
||
|
|
"height": 219
|
||
|
|
},
|
||
|
|
"id": "xqNHhmaAr8qx",
|
||
|
|
"outputId": "39811601-8c0c-4bb0-c6b2-6857b43fd3df"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"def some_function():\n",
|
||
|
|
" function_variable = \"This is a function variable!\"\n",
|
||
|
|
" print(function_variable)\n",
|
||
|
|
"\n",
|
||
|
|
"some_function()\n",
|
||
|
|
"function_variable"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"This is a function variable!\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"output_type": "error",
|
||
|
|
"ename": "NameError",
|
||
|
|
"evalue": "ignored",
|
||
|
|
"traceback": [
|
||
|
|
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
|
||
|
|
"\u001b[0;31mNameError\u001b[0m Traceback (most recent call last)",
|
||
|
|
"\u001b[0;32m<ipython-input-94-9c38147d2171>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m 4\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 5\u001b[0m \u001b[0msome_function\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 6\u001b[0;31m \u001b[0mfunction_variable\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
|
||
|
|
"\u001b[0;31mNameError\u001b[0m: name 'function_variable' is not defined"
|
||
|
|
]
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "Qw-hVhH2qm37"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Functions can also define variables to be used in the global scope, using the `global` key."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "uOIZC5K-qrYO",
|
||
|
|
"outputId": "a9766d22-09a1-4969-8d1c-080f3e9a22de"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"def foo():\n",
|
||
|
|
" global global_variable\n",
|
||
|
|
" # If we try printing global_variable here, we would get a not defined error\n",
|
||
|
|
" global_variable = \"This is a global variable!\"\n",
|
||
|
|
" print(global_variable)\n",
|
||
|
|
"\n",
|
||
|
|
"def bar():\n",
|
||
|
|
" print(global_variable)\n",
|
||
|
|
"\n",
|
||
|
|
"foo()\n",
|
||
|
|
"bar()"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"This is a global variable!\n",
|
||
|
|
"This is a global variable!\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "YL4llM39tyT8"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can define functions within functions."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "D4B3iAjMtxkB",
|
||
|
|
"outputId": "bf6907d2-d5da-4249-eed7-567fca62244d"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"def main_function(a):\n",
|
||
|
|
"\n",
|
||
|
|
" def helper_function(a):\n",
|
||
|
|
" return int(a)\n",
|
||
|
|
"\n",
|
||
|
|
" print(a)\n",
|
||
|
|
" b = helper_function(a)\n",
|
||
|
|
" print(b)\n",
|
||
|
|
"\n",
|
||
|
|
"# Calling the main function\n",
|
||
|
|
"main_function(2.0)\n",
|
||
|
|
"helper"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"2.0\n",
|
||
|
|
"2\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "b-2jwYYrDfBk"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Functions can take in functions as variables."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "i8spJVIcDh-q",
|
||
|
|
"outputId": "62960e80-7965-485a-b33f-538e4cec4910"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"def function_taker(a, func):\n",
|
||
|
|
" return func(a)\n",
|
||
|
|
"\n",
|
||
|
|
"function_taker(1.0, int)\n",
|
||
|
|
"\n",
|
||
|
|
"int(1.0)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"text/plain": [
|
||
|
|
"1"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 70
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "Esm5wFH7DtZY"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can seperately define the function we need to pass."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "bXQl4FYNDxkc",
|
||
|
|
"outputId": "91215438-b79e-4292-9b20-5061e34a466a"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"def parameter_function(x):\n",
|
||
|
|
" return x + 5\n",
|
||
|
|
"\n",
|
||
|
|
"def function_taker(a, func):\n",
|
||
|
|
" return func(a)\n",
|
||
|
|
"\n",
|
||
|
|
"function_taker(1.0, parameter_function)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"text/plain": [
|
||
|
|
"6.0"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 71
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "c5Qy2L5MECoy"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can also use `lambda` functions."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "6fgwBmOPEExC",
|
||
|
|
"outputId": "cc962a91-ed87-43bc-954d-acf91f100304"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"def function_taker(a, func):\n",
|
||
|
|
" return func(a)\n",
|
||
|
|
"\n",
|
||
|
|
"function_taker(1.0, lambda x: x + 5)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"text/plain": [
|
||
|
|
"6.0"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 72
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "hQYjc2UOEPpX"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"`lambda` functions can use variables in their parent scope."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "m18mroJjEVWW",
|
||
|
|
"outputId": "134166b8-cf52-4875-a13c-dd022bfb344d"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"num_to_add = 10\n",
|
||
|
|
"\n",
|
||
|
|
"def function_taker(a, func):\n",
|
||
|
|
" return func(a)\n",
|
||
|
|
"\n",
|
||
|
|
"function_taker(1.0, lambda x: x + num_to_add)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"text/plain": [
|
||
|
|
"11.0"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 73
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "z2XL4mZrE5fO"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can also have recursive functions."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "7exW7ny2E8x5",
|
||
|
|
"outputId": "f5aefd16-d3ee-49f7-91ba-75e50195b3eb"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"def print_positive_numbers(num):\n",
|
||
|
|
" if num <= 0:\n",
|
||
|
|
" print(\"Done!\")\n",
|
||
|
|
" else:\n",
|
||
|
|
" print(num)\n",
|
||
|
|
" print_positive_numbers(num-1)\n",
|
||
|
|
"\n",
|
||
|
|
"print_positive_numbers(10)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"10\n",
|
||
|
|
"9\n",
|
||
|
|
"8\n",
|
||
|
|
"7\n",
|
||
|
|
"6\n",
|
||
|
|
"5\n",
|
||
|
|
"4\n",
|
||
|
|
"3\n",
|
||
|
|
"2\n",
|
||
|
|
"1\n",
|
||
|
|
"Done!\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "02E4_aVwAiAu"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"## Classes\n",
|
||
|
|
"\n",
|
||
|
|
"We can define classes ourselves as well."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "BeQle4jYo6tp",
|
||
|
|
"outputId": "c9b68fb0-fc5c-4d25-933d-dd8dac0c5ca1"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"class Foo():\n",
|
||
|
|
" # Alternative: class Foo(object) - all Python classes inherits 'object'\n",
|
||
|
|
" class_variable = 'same' # class variable\n",
|
||
|
|
"\n",
|
||
|
|
" # Optional constructor\n",
|
||
|
|
" def __init__(self, x):\n",
|
||
|
|
" # first parameter \"self\" for instance reference, like \"this\" in JAVA\n",
|
||
|
|
" self.x = x\n",
|
||
|
|
"\n",
|
||
|
|
" # instance method\n",
|
||
|
|
" def print_x(self): # instance reference is required for all instance variables\n",
|
||
|
|
" print(self.x)\n",
|
||
|
|
"\n",
|
||
|
|
" # class method\n",
|
||
|
|
" @classmethod\n",
|
||
|
|
" def modify_class_variable(cls):\n",
|
||
|
|
" cls.class_variable = 'changed'\n",
|
||
|
|
"\n",
|
||
|
|
" # static method\n",
|
||
|
|
" @staticmethod\n",
|
||
|
|
" def print_hello():\n",
|
||
|
|
" print(\"Hello!\")\n",
|
||
|
|
"\n",
|
||
|
|
"print(Foo.class_variable)\n",
|
||
|
|
"\n",
|
||
|
|
"obj1 = Foo(6)\n",
|
||
|
|
"obj1.print_x()\n",
|
||
|
|
"print(obj1.class_variable)\n",
|
||
|
|
"\n",
|
||
|
|
"obj2 = Foo(5)\n",
|
||
|
|
"obj2.print_x()\n",
|
||
|
|
"print(obj2.class_variable)\n",
|
||
|
|
"\n",
|
||
|
|
"obj1.modify_class_variable()\n",
|
||
|
|
"print(obj1.class_variable)\n",
|
||
|
|
"print(obj2.class_variable)\n",
|
||
|
|
"print(Foo.class_variable)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"same\n",
|
||
|
|
"6\n",
|
||
|
|
"same\n",
|
||
|
|
"5\n",
|
||
|
|
"same\n",
|
||
|
|
"changed\n",
|
||
|
|
"changed\n",
|
||
|
|
"changed\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "SHUx7oQLDBrb"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can also inherit classes."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "t36HuUmqo6tp",
|
||
|
|
"outputId": "92b5170f-623a-4e7b-86d8-3ec5ee1b87f4"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# Inherits variables and methods\n",
|
||
|
|
"class Bar(Foo):\n",
|
||
|
|
" pass\n",
|
||
|
|
"\n",
|
||
|
|
"obj = Bar(3)\n",
|
||
|
|
"obj.print_x()"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"3\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "Qx7hqK-Co6tq"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"## Iterables\n",
|
||
|
|
"\n",
|
||
|
|
"There are several different built-in iterable objects in `Python`."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"id": "V3gtHrbdzkJD"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# immutable iterables, with fixed size\n",
|
||
|
|
"astring = str()\n",
|
||
|
|
"atuple = tuple()\n",
|
||
|
|
"\n",
|
||
|
|
"# mutable iterables, not fixed size\n",
|
||
|
|
"alist = list() # linear\n",
|
||
|
|
"adict = dict() # hash table, stores (key, value) pairs\n",
|
||
|
|
"aset = set() # hash table, like dict but only stores keys"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": []
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "8DMKgRW_z6Vr"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Size of any iterable can be obtained with `len`."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "JTJu6az0o6tq",
|
||
|
|
"outputId": "771e1f1e-b717-4e31-ea2e-c7cca396db87"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"print(len(alist))"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"0\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "WfWoqlvG2rpR"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"### List\n",
|
||
|
|
"\n",
|
||
|
|
"Lists store an ordered list of elements."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"id": "1BVNv_Clo6tr"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"\"\"\"\n",
|
||
|
|
"List:\n",
|
||
|
|
"\n",
|
||
|
|
" mutable - not hashable: can't be used as dictionary keys\n",
|
||
|
|
" dynamic size\n",
|
||
|
|
" allows duplicates and inconsistent element types\n",
|
||
|
|
" dynamic array implementation\n",
|
||
|
|
"\"\"\"\n",
|
||
|
|
"alist = [] # equivalent to list()\n",
|
||
|
|
"alist = [1,2,3,4,5] # initialized list"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": []
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "Drqeatru3clX"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can access and modify list elements, similar to strings."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "YzP2qig73aip",
|
||
|
|
"outputId": "4dfb5815-b940-45d8-aae7-2bc21a5a370e"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"print(alist[0])\n",
|
||
|
|
"alist[0] = 5\n",
|
||
|
|
"print(alist)\n",
|
||
|
|
"\n",
|
||
|
|
"print(\"-\"*10)\n",
|
||
|
|
"# list indexing\n",
|
||
|
|
"print(alist[0]) # get first element (at index 0)\n",
|
||
|
|
"print(alist[-2]) # get 2nd to last element (at index len-1)\n",
|
||
|
|
"print(alist[3:]) # get elements starting from index 3 (inclusive)\n",
|
||
|
|
"print(alist[:3]) # get elements stopping at index 3 (exclusive)\n",
|
||
|
|
"print(alist[2:4]) # get elements within index range [2,4)\n",
|
||
|
|
"print(alist[6:]) # prints nothing because index is out of range"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"5\n",
|
||
|
|
"[5, 2, 3, 4, 5]\n",
|
||
|
|
"----------\n",
|
||
|
|
"5\n",
|
||
|
|
"4\n",
|
||
|
|
"[4, 5]\n",
|
||
|
|
"[5, 2, 3]\n",
|
||
|
|
"[3, 4]\n",
|
||
|
|
"[]\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "u5RQCObM3seH"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can reverse a list."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "NBDj-DxF30CT",
|
||
|
|
"outputId": "a6550485-3a95-4177-cc93-a06fd065dec5"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"alist[::-1] # returns a reversed list"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"text/plain": [
|
||
|
|
"[5, 4, 3, 2, 5]"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 84
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "QzpmPx0j32R-"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can call methods on a list."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "dyaIpKgW36bI",
|
||
|
|
"outputId": "653230a9-b8ed-4102-bd8a-7c7a66b4fef7"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"alist.append(\"new item\") # insert at end\n",
|
||
|
|
"alist.insert(0, \"new item\") # insert at index 0\n",
|
||
|
|
"alist.extend([2,3,4]) # concatenate lists\n",
|
||
|
|
"# above line is equivalent to alist += [2,3,4]\n",
|
||
|
|
"alist.index(\"new item\") # search by content\n",
|
||
|
|
"alist.remove(\"new item\") # remove by content\n",
|
||
|
|
"popped = alist.pop(0) # remove by index\n",
|
||
|
|
"print(alist)\n",
|
||
|
|
"print(popped)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"[2, 3, 4, 5, 'new item', 2, 3, 4]\n",
|
||
|
|
"5\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "0c8id4IG4jpB"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can check if an element is contained in a list."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "9IJJhB1y3s_r",
|
||
|
|
"outputId": "3cd7e583-4fbc-4f56-f865-6b404abb469a"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"if \"new item\" in alist:\n",
|
||
|
|
" print(\"found\")"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"found\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "6pinHv3t0B5B"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"### Tuples\n",
|
||
|
|
"\n",
|
||
|
|
"Tuples allow us to store immutable lists."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"id": "_ec4BTva0eqw"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"\"\"\"\n",
|
||
|
|
"Tuple:\n",
|
||
|
|
"\n",
|
||
|
|
" immutable - hashable: can be used as a dictionary key\n",
|
||
|
|
" fixed size: no insertion or deletion\n",
|
||
|
|
"\"\"\"\n",
|
||
|
|
"atuple = (1,2,3,4,5)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": []
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"id": "mOv1HOqlq00b"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"atuple = (1)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": []
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "PByClj1mrCCf",
|
||
|
|
"outputId": "08538db3-c458-4831-85d2-38ef329f4835"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"type(atuple)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"text/plain": [
|
||
|
|
"int"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 93
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "6ZOInlx72J1Z"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Indexing or traversal of a `tuple` is the same as that of a `list`."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"id": "6AaRSa-82JMN"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# Defining tuple from a list\n",
|
||
|
|
"atuple = tuple([1,2,3])"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": []
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "xsscT5XJ2Jci"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can use tuples as dictionary keys.\n",
|
||
|
|
"\n"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"id": "4d0__BN6o6tq"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"ngram = (\"a\", \"cat\")\n",
|
||
|
|
"d = dict()\n",
|
||
|
|
"d[ngram] = 10\n",
|
||
|
|
"d[ngram] += 1"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": []
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "U-a6t5xc4rG6"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can use named tuples to improve readability."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "rdRo7jvio6t4",
|
||
|
|
"outputId": "f47d9aa0-3c66-48cc-9449-ee00b9466f6a"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"from collections import namedtuple\n",
|
||
|
|
"Point = namedtuple('Point', 'x y')\n",
|
||
|
|
"pt1 = Point(1.0, 5.0)\n",
|
||
|
|
"pt2 = Point(2.5, 1.5)\n",
|
||
|
|
"print(pt1.x, pt1.y)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"1.0 5.0\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "2MeHbcuu493p"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"### Dictionary\n",
|
||
|
|
"\n",
|
||
|
|
"Dictionaries are useful for storing key - value pairs."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "FgjMce7lo6t6",
|
||
|
|
"outputId": "4af30c7b-f520-404b-cab0-32b650d13d07"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"\"\"\"\n",
|
||
|
|
"Dict:\n",
|
||
|
|
"\n",
|
||
|
|
" not hashable\n",
|
||
|
|
" dynamic size\n",
|
||
|
|
" no duplicates allowed\n",
|
||
|
|
" hash table implementation which is fast for searching\n",
|
||
|
|
"\n",
|
||
|
|
"\"\"\"\n",
|
||
|
|
"adict = {} # same as dict()\n",
|
||
|
|
"adict = {'dog': 10, 'bird': 5, 'lion': 8}\n",
|
||
|
|
"print(adict)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"{'dog': 10, 'bird': 5, 'lion': 8}\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "qDbczIwk5Y_6"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can get keys, values or items in a dictionary."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "uaLYZomJ5f6s",
|
||
|
|
"outputId": "e3d4fd76-b291-4e37-9fc5-5b0c3c5f782c"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"print(adict.keys())\n",
|
||
|
|
"print(adict.values())\n",
|
||
|
|
"print(adict.items())"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"dict_keys(['dog', 'bird', 'lion'])\n",
|
||
|
|
"dict_values([10, 5, 8])\n",
|
||
|
|
"dict_items([('dog', 10), ('bird', 5), ('lion', 8)])\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "bSvTjzwa5za7"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can access an item with a specific key."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "1DAetNu452bQ",
|
||
|
|
"outputId": "7df7eb6b-ff2e-4773-e4ac-17d9e881ec8e"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"print(adict['lion'])"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"8\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "YYc3kd4L6NWA"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can check if a key exists in a dictionary. This is needed since accessing non-existent keys throws an error."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/",
|
||
|
|
"height": 167
|
||
|
|
},
|
||
|
|
"id": "FHM5P_3Q6aSr",
|
||
|
|
"outputId": "2db8e3ce-7aff-462b-e60e-ca8ba41b3566"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"adict['tiger']"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "error",
|
||
|
|
"ename": "KeyError",
|
||
|
|
"evalue": "ignored",
|
||
|
|
"traceback": [
|
||
|
|
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
|
||
|
|
"\u001b[0;31mKeyError\u001b[0m Traceback (most recent call last)",
|
||
|
|
"\u001b[0;32m<ipython-input-98-52009ea6fcff>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0madict\u001b[0m\u001b[0;34m[\u001b[0m\u001b[0;34m'tiger'\u001b[0m\u001b[0;34m]\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
|
||
|
|
"\u001b[0;31mKeyError\u001b[0m: 'tiger'"
|
||
|
|
]
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "tsgXho126QD5",
|
||
|
|
"outputId": "da00a688-d2e6-40c0-b1ad-f338a019b47d"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"if 'tiger' in adict:\n",
|
||
|
|
" print(adict[key])\n",
|
||
|
|
"else:\n",
|
||
|
|
" print('Key not found.')"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"Key not found.\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "UGE08yH96mp7"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Insert new keys."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"id": "JicEI5sj6oFb"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"adict['tiger'] = 1"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": []
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "h16DZ3uk6rec"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Modify existing keys."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"id": "_oCgyCAP6yQF"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"adict['lion'] = 20"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": []
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "79kmfD1L6tvR"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Traversing dictionaries.\n"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "0mShrqZI5Rco",
|
||
|
|
"outputId": "924011d9-192e-4bb2-b6b0-71db73585535"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"for key in adict:\n",
|
||
|
|
" print(key, adict[key])"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"dog 10\n",
|
||
|
|
"bird 5\n",
|
||
|
|
"lion 8\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "0Oarhwm87Bsf"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Traversing key, value pairs together."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "asfYaluB7Ebn",
|
||
|
|
"outputId": "978f1123-93ed-48e3-d8b8-57f8bebb31ee"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"for key, val in adict.items():\n",
|
||
|
|
" print(key, val)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"dog 10\n",
|
||
|
|
"bird 5\n",
|
||
|
|
"lion 20\n",
|
||
|
|
"tiger 1\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "f6wWiDFs7aPU"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"### DefaultDict\n",
|
||
|
|
"\n",
|
||
|
|
"`DefaultDict` is a special dictionary that returns a default value when a key queried isn't found."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "wm4eqxU67xJY",
|
||
|
|
"outputId": "b739fdc0-8a73-4263-d588-f7f6c3e6f1fe"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"from collections import defaultdict\n",
|
||
|
|
"\n",
|
||
|
|
"adict = defaultdict(int)\n",
|
||
|
|
"adict['cat'] = 5\n",
|
||
|
|
"print(adict['cat'])\n",
|
||
|
|
"print(adict['dog'])"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"5\n",
|
||
|
|
"0\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "PlHxXbUg77XJ"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"It is also possible to pass a custom function."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "iPEZbjpn7ney",
|
||
|
|
"outputId": "63deabcc-acad-4ede-d2dc-85461013ffa0"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"from collections import defaultdict\n",
|
||
|
|
"adict = defaultdict(lambda: 'unknown')\n",
|
||
|
|
"adict['cat'] = 'feline'\n",
|
||
|
|
"print(adict['cat'])\n",
|
||
|
|
"print(adict['dog'])"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"feline\n",
|
||
|
|
"unknown\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "lYQI1E858MF2"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"### Counter\n",
|
||
|
|
"\n",
|
||
|
|
"`Counter` is a dictionary with default value of 0."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "Z14YHrWyo6t8",
|
||
|
|
"outputId": "4fa122e0-6d45-4968-ff1e-ca4348bd68cb"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"from collections import Counter\n",
|
||
|
|
"\n",
|
||
|
|
"# initialize and modify empty counter\n",
|
||
|
|
"counter1 = Counter()\n",
|
||
|
|
"counter1['t'] = 10\n",
|
||
|
|
"counter1['t'] += 1\n",
|
||
|
|
"counter1['e'] += 1\n",
|
||
|
|
"print(counter1)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"Counter({'t': 11, 'e': 1})\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "94SMZI9y8W_I"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can initialize counters from other iterables."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "7GltlZgl8acL",
|
||
|
|
"outputId": "c699aede-d9bd-4a61-9e0e-7e1fe3ee72be"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"counter2 = Counter(\"letters to be counted\")\n",
|
||
|
|
"print(counter2)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"Counter({'e': 4, 't': 4, ' ': 3, 'o': 2, 'l': 1, 'r': 1, 's': 1, 'b': 1, 'c': 1, 'u': 1, 'n': 1, 'd': 1})\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "TCajDMH98hIZ"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can perform operations between counters."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "HxGq9Ex18f3l",
|
||
|
|
"outputId": "9540d335-9645-4bae-bf90-2f1896298ffa"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"print(\"1\", counter1 + counter2)\n",
|
||
|
|
"print(\"2\", counter1 - counter2)\n",
|
||
|
|
"print(\"3\", counter1 or counter2) # or for intersection, and for union"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"1 Counter({'t': 15, 'e': 5, ' ': 3, 'o': 2, 'l': 1, 'r': 1, 's': 1, 'b': 1, 'c': 1, 'u': 1, 'n': 1, 'd': 1})\n",
|
||
|
|
"2 Counter({'t': 7})\n",
|
||
|
|
"3 Counter({'t': 11, 'e': 1})\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "mdlqrgDF81yr"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can use other special methods on counters. Check out the docs for more!"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "Fxgl9n7N86ic",
|
||
|
|
"outputId": "61e41917-25ab-44bd-bdc2-964bd137e49a"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"counter2.most_common(5)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"text/plain": [
|
||
|
|
"[('e', 4), ('t', 4), (' ', 3), ('o', 2), ('l', 1)]"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 107
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "2s8_am1J9PwW"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can iterate list of tuples."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "xWANB8hj9UY0",
|
||
|
|
"outputId": "2fbd266e-1c26-495b-87b1-d39301c14f0b"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"for k,v in counter2.most_common(5):\n",
|
||
|
|
" print(k, v)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"e 4\n",
|
||
|
|
"t 4\n",
|
||
|
|
" 3\n",
|
||
|
|
"o 2\n",
|
||
|
|
"l 1\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "YTgf-Qwj7Kpw"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"### Set\n",
|
||
|
|
"\n",
|
||
|
|
"Set is a special dictionary without values."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"id": "wmhE3Zmeo6t7",
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"outputId": "42b54c03-c921-439f-fcb9-e70cc932c742"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"aset = set()\n",
|
||
|
|
"aset.add('a')\n",
|
||
|
|
"aset"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"text/plain": [
|
||
|
|
"{'a'}"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 109
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "oAVaGb2g7SLC"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can use sets to remove duplicates from a list."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "5qyT88U37VWR",
|
||
|
|
"outputId": "697c6108-614f-455e-8245-040f388bb87f"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"alist = [5,2,3,3,3,4,3]\n",
|
||
|
|
"alist = list(set(alist))\n",
|
||
|
|
"print(alist)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"[2, 3, 4, 5]\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "mWuYLCwutwPN",
|
||
|
|
"outputId": "e0dd8d5a-f04e-444f-f5cd-b16e3458ec71"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"set(alist)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"text/plain": [
|
||
|
|
"{2, 3, 4, 5}"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 116
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "Sh6-iKkUtcv4",
|
||
|
|
"outputId": "fe3824bc-5d83-494b-bd9c-824e7b0a0f0e"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"list(set(alist))"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"text/plain": [
|
||
|
|
"[2, 3, 4, 5]"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 115
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "IEG17z-39dkT"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"### Sorting\n",
|
||
|
|
"\n",
|
||
|
|
"We can sort iterables."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "yr0Npa5do6t8",
|
||
|
|
"outputId": "72da5b12-d851-49c5-be0b-fd7cd6385a7c"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"a = [4,6,1,7,0,5,1,8,9]\n",
|
||
|
|
"a = sorted(a)\n",
|
||
|
|
"print(a)\n",
|
||
|
|
"a = sorted(a, reverse=True)\n",
|
||
|
|
"print(a)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"[0, 1, 1, 4, 5, 6, 7, 8, 9]\n",
|
||
|
|
"[9, 8, 7, 6, 5, 4, 1, 1, 0]\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "N6sPZZUV9k-X"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can sort iterables containing tuples."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "fvdUq_7Lo6t8",
|
||
|
|
"outputId": "91e3ad57-3dce-4fac-e49c-55d03d88f81f"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"# sorting\n",
|
||
|
|
"a = [(\"cat\",1), (\"dog\", 3), (\"bird\", 2)]\n",
|
||
|
|
"a = sorted(a)\n",
|
||
|
|
"print(a)\n",
|
||
|
|
"b = sorted(a, key=lambda item: item[1])\n",
|
||
|
|
"print(b)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"[('bird', 2), ('cat', 1), ('dog', 3)]\n",
|
||
|
|
"[('cat', 1), ('bird', 2), ('dog', 3)]\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "Z88BCni79v-Q"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can pass a function we define outside instead of a lambda function."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "jCM6jPbv91xH",
|
||
|
|
"outputId": "117216f7-2c49-412b-f866-269d3ef76e47"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"def sorting_key(item):\n",
|
||
|
|
" return item[1]\n",
|
||
|
|
"\n",
|
||
|
|
"sorted(a, key=sorting_key)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "execute_result",
|
||
|
|
"data": {
|
||
|
|
"text/plain": [
|
||
|
|
"[('cat', 1), ('bird', 2), ('dog', 3)]"
|
||
|
|
]
|
||
|
|
},
|
||
|
|
"metadata": {
|
||
|
|
"tags": []
|
||
|
|
},
|
||
|
|
"execution_count": 167
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "HDG7xi4M-U_t"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can sort dictionaries the same way."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "19oDadMwo6t-",
|
||
|
|
"outputId": "14abc53b-d069-4a3c-dc41-9b0a9235c2ab"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"adict = {'cat':3, 'bird':1}\n",
|
||
|
|
"print(sorted(adict.items(), key=lambda x:x[1]))"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"[('bird', 1), ('cat', 3)]\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "aQywFVev-ZzH"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"### List Comprehension\n",
|
||
|
|
"\n",
|
||
|
|
"Instead of using `for` loops every time, we can use list comprehensions to create new lists or other iterables."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "8eGjNjf2o6t_",
|
||
|
|
"outputId": "3f774852-8a93-4bfa-df5c-a562fc64cf28"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"\"\"\"\n",
|
||
|
|
"for i in range(len(sent)):\n",
|
||
|
|
" sent[i] = sent[i].lower().split(\" \")\n",
|
||
|
|
"\"\"\"\n",
|
||
|
|
"\n",
|
||
|
|
"sent = [\"i am good\", \"a beautiful day\", \"HELLO FRIEND\"]\n",
|
||
|
|
"sent1 = [s.lower().split(\" \") for s in sent]\n",
|
||
|
|
"print(sent1)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"[['i', 'am', 'good'], ['a', 'beautiful', 'day'], ['hello', 'friend']]\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "JL9NYWLg-1nx"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can have conditions."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "dNedRQmK-uG0",
|
||
|
|
"outputId": "a1dfab90-c565-4115-f51e-46a59cf5a035"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"sent2 = [s.lower().split(\" \") for s in sent if len(s) > 10]\n",
|
||
|
|
"print(sent2)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"[['a', 'beautiful', 'day'], ['hello', 'friend']]\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "y3nTEdUU--QQ"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"We can create other iterables the same way."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "0LMW-AFv_GPy",
|
||
|
|
"outputId": "bb1da3f4-2e21-488e-a712-efa6c2896dde"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"keys = ['a', 'b', 'c']\n",
|
||
|
|
"dict1 = {k: i for i, k in enumerate(keys)}\n",
|
||
|
|
"print(dict1)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"{'a': 0, 'b': 1, 'c': 2}\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "Yio2kKK5_SQi"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"Another useful function we can use is `zip`."
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "code",
|
||
|
|
"metadata": {
|
||
|
|
"colab": {
|
||
|
|
"base_uri": "https://localhost:8080/"
|
||
|
|
},
|
||
|
|
"id": "_u3k-7Xr_eH0",
|
||
|
|
"outputId": "9270494d-c9f2-4fc5-fa39-53fca8351bd6"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"keys = ['a', 'b', 'c']\n",
|
||
|
|
"values = [10, 5, 30]\n",
|
||
|
|
"zipped = zip(keys, values)\n",
|
||
|
|
"print(zipped) # zip object\n",
|
||
|
|
"print(list(zipped)) # pass to list to unzip\n",
|
||
|
|
"\n",
|
||
|
|
"for k, v in zip(keys, values):\n",
|
||
|
|
" print(k, v)"
|
||
|
|
],
|
||
|
|
"execution_count": null,
|
||
|
|
"outputs": [
|
||
|
|
{
|
||
|
|
"output_type": "stream",
|
||
|
|
"text": [
|
||
|
|
"<zip object at 0x7fc747a65640>\n",
|
||
|
|
"[('a', 10), ('b', 5), ('c', 30)]\n",
|
||
|
|
"a 10\n",
|
||
|
|
"b 5\n",
|
||
|
|
"c 30\n"
|
||
|
|
],
|
||
|
|
"name": "stdout"
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
"cell_type": "markdown",
|
||
|
|
"metadata": {
|
||
|
|
"id": "wugqn01Eo6uK"
|
||
|
|
},
|
||
|
|
"source": [
|
||
|
|
"## Q&A\n",
|
||
|
|
"\n",
|
||
|
|
"Question time!"
|
||
|
|
]
|
||
|
|
}
|
||
|
|
]
|
||
|
|
}
|